General description

lmv721 (single) and LMV722 (dual) are low noise, low noise voltage and low -power computing amplifiers, which can be designed as widely used. LMV721/LMV722 has a unit gain bandwidth of 10MHz, a conversion rate of 5V/US, and the static current of 930UA/amplifier at 2.2V. LMV721/722 is designed to provide the best performance in low -pressure and low noise systems. They provide rail pairing output swing into heavy loads. The input co -mode voltage range includes grounding, and the maximum input offset voltage is 3.5mV (over temperature) LMV721/LMV722. Their capacitance load capacity is also good at low power voltage. The working range is 2.2 volt to 5.5 volts. The chip uses the national advanced sub -micron technology to make silicon grid BICMOS technology. Single version, LMV721, provides 5 stitches SOT2 3-5 and SC-70 (new) packaging. Double version, LMV722, in SO-8 and MSOP-8 packs.

Features

(for a typical 5 V power supply value; unless there are other instructions)

Guarantee 2.2V and 5.0V performance

Low power current LMV721 /2 930 Wei'an/amplifier@2.2V

The gain bandwidth of the high unit 10MHz

Rail output amplitude@600Ω load 120mV, 2.2V from any orbit@2kΩ load 50mv, 2.2V from any orbit

Enter the co-mode voltage range includes ground

Silicon powder #8482;, SC70-5 package 2.0x2.0x1.0 mm

Input voltage noise 9 f 1kHz

Application

Wireless phone

Active filter and buffer

Absolute maximum rated value (Note 1)

If you need military/aerospace equipment,

ESD tolerance (Note 2)

2000 volt human model

Machine model 200V

Differential input voltage ± power voltage

Power voltage (V+--V-) 5.5 volts

Welding information

Infrared 235 degrees Celsius

Storage temperature. Temperature range -65 degrees Celsius to 150 degrees Celsius

Jacking Temperature (Note 4) 150 ℉

working rated value (Note 3)

Power supply voltage 2.2V to 5.0V [123 ]

Temperature range 40 ℉ C ≤T J≤8512 C

Thermal resistance (θja)

Silus powder SC70-5 packaging 440∏c/w

Micro SOT33-5 Packaging 265 degrees Celsius

so so so so so Component, 8-sales surface installation 190 ° C/W

MSOP component, 8-pin mini surface

Installation

235 degrees Celsius/tile SO-PKEGE, 14-pin surface installation installation 145 ° C/W

2.2V DC Phase feature

Unless there are other regulations, it is guaranteed to guarantee TJ 25 ° C. V+ 2.2V, V- 0V, all limits of vcm v+/2, VO V+/2, and R GT; 1 MΩ. Black body restrictions are suitable for extreme temperatures.

5V DC special characteristics

Unless there are other regulations, it is guaranteed to guarantee TJ 25 ° C. V+ 5V, V- 0V, all limits of vcm v+/2, VO V+/2, and RL GT; 1 MΩ. Black body restrictions are suitable for extreme temperature

5V AC electrical characteristics

Unless there are other regulations, it is guaranteed to guarantee TJ 25 ° C. V+ 5V, V- 0V, VCM V all limits+/2, VO V+/2, and R GT; 1 MΩ. Black body restrictions are suitable for extreme temperatures.

Note 1: Absolute maximum rated value indicates the limit that the device may be damaged. When the working rated value indicates that the device is in the state, the device tends to work normally, but it cannot guarantee specific performance. For guarantee specifications and test conditions, see electrical characteristics.

Note 2: Human model, 1.5 kΩ connects 100 PF. Machine model, 200Ω with 100 PF series.

Note 3: Applicable to the operation of single power and division. Under the condition of rising ambient temperature, continuous short -circuit operations may lead to more than 150 ° C by a maximum allowed. Long -term output current exceeding 30 mAh may adversely affect reliability.

Note 4: The maximum power consumption is the functions of TJ (MAX), θJa, and TA. The maximum allowable power consumption at any ambient temperature is p D (tj (max) -t A)/θJa. All numbers are suitable for packaging directly welded to the PC board.

Note 5: Typical values represent the most likely parameter model.

Note 6: All limits are guaranteed by testing or statistical analysis.

Note 7: Connect with a 1V step input voltage follower. The specified number is slower in the positive and negative conversion rate

typical performance features

Application description

1.0 LMV721/722 advantages. LMV721/722 packs of small footprint printing circuit boards make small electronic products, such as mobile phones, paging machines, or other portable systems. Low -key LMV721/722 can be used for PCMCIA III cards. Signal integrity. The signal can pick up the noise between the signal source and the amplifier. By using a smaller amplifier component, LMV721/722 can be placed at a more signal source to reduce noise pickup and improve signal integrity. Simplified circuit board layout. These products help you avoid using long PC tracking in your PC plate layout. This means that there are no additional components, such as capacitors and resistors, you need to filter out unwanted signals caused by interference between long PC records. Low power supply current. These devices will help you extend battery life to the greatest extent. They are the ideal choice of battery power supply system. The power supply voltage is low. National provides guarantee performance under 2.2V and 5V voltage. This guarantees the entire battery life of operation. Rail -to -track losses. The rail -to -orbit output width provides the maximum possible dynamic range at the output end. This is especially important when working at low power voltage. Input includes ground. Allow the direct induction single power supply operation near the ground input. Protection should be provided to prevent the input voltage from exceeding -0.3V (when 25 degrees Celsius) should be provided. Input, clamp the diode with a resistor to the IC input terminal.

2.0 capacitance load tolerance

LMV721/722 can directly drive the unit gain of 4700pf without oscillation. The unit gain follower is the most sensitive configuration of the capacitor load. Direct capacitor loading reduces the phase of the amplifier. The combination of the amplifier output impedance and the capacitor causes phase lag. This can cause the underwriting pulse response or oscillation. To drive heavier loads, the circuit in Figure 1 can be used.

In FIG. 1, the isolation resistance RISO and the load capacitor CL form a pole, which increases the stability of the stability throughout the system by increasing the phase. The ideal performance depends on the value of RISO. The larger the Riso resistance, the larger the VOUT. Figure 2 is a waveform of the output Figure 1, using 100kΩ to represent RISO, and 2000 μF to represent chlorine.

The circuit in FIG. 3 is improvement of the circuit in the figure 1 because it provides DC accuracy and exchange stability. If there is a load resistor in Figure 1, the output is the voltage divided by RISO and the load resistance. Instead, in Figure 3, RF provides DC accuracy to provide DC accuracy to connect vehicle recognition numbers and driving recognition numbers. Be careful when choosing an RF value, because LMV721/722. CF and RISO are used to offset phase margins that give up high -frequency componentsThe output signal returns to the reverse input of the amplifier, so as to maintain the phase margin in the entire feedback

Application instructions (continued)

cycle. By increasing the value of CF. This will reducing the pulse response in turn.

3.0 input bias current eliminates

LMV721/722 series with bipolar input level. The typical input bias current of LMV721/722 is 260NA, 5V Sup Ply. Therefore, the 100kΩ input resistance will cause a 26MV error voltage. By balancing the two reverse resistance values and non -inverse inputs, the input bias current of the amplifier will be reduced. The circuit in FIG. 4 indicates how to eliminate the error caused by the input bias current.

4.0 Typical single -power application circuit

4.1 Differential amplifier

Differential amplifier allows the two inputs to reduce the time difference, Or in special circumstances, a signal is eliminated for two inputs. It is a useful computing amplifier that transitions to a single -end conversion or rejects co -model signals.

4.2 Instrument circuit

The input impedance of the previous differential amplifier was set on the grounds of the resistance R1, R2, R3, and R4 settings. In order to eliminate the problem of low input impedance, one method is to use the follower of the previous input of the voltage, as shown in the instrument amplifier.

4.2.1 Three -handed instrument amplifier

LMV721/722 can be used to build three operations input amplifiers, as shown in Figure 6

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123] The first level of the instrument amplifier is the differential input, the differential output amplifier, and two voltage followers. These two voltage followers ensure that the input impedance is greater than 100MΩ. The gain of the instrument amplifier is set by the ratio of R2/R1. R3 should equal R1 and R4 equals R2. The matching of R3 to R1 and R4 to R2 affects CMRR. The resistor should be used for good CMRR super temperature and low drift. Make R4 slightly smaller than R2 and plus one equivalent to R2 and R4 will allow adjustment of CMRR to achieve the best results.

4.2.2 dual operation amplifier amplifier amplifier

The dual -transportation instrument amplifier can also be used to make high input impedance DC splitter (Figure 7). Like the two op amp circuits, the instrument amplifier needs accurate resistance matching to obtain a good co -mode suppression ratio. 4 Rand should equal to R1, R3 should equal R2.

4.3 Single power supply inverter amplifier

It may be negative in the input signal to enter the amplifier. Because the amplifier works in a single power supply voltage, using the R3 and R4 divisor to make the amplifier bias,Make the input signal in the input public voltage range of the amplifier. The capacitor C1 is placed in the resistance R1 source, text, text. The value of the value of R1 and C1 affects the deadline, FC 1/2πr1c1. Therefore, the output signal is concentrated near the middle power supply (if the voltage provides V+/2 input in input). The output can swing to two orbit to maximize the signal -to -noise ratio in the low pressure system.

4.4 Active filter

4.4.1 Simple low -pass active filter

Simple low -pass filter shown 9 shown. Its low frequency gain (ω → O) is defined by -R3/R1. This allows low -frequency gains other than the unit. The filter has -20db/decade attenuation after the angular frequency FC. The choice of R2 should be equal to the parallel combination of R1 and R3 to minimize the error caused by the BAIS current. The response of the frequency filter is shown in Figure 10.

Note that the single transportation amplifier has the active filter to require low quality factor, Q (≤10), low frequency (≤5kHz), low gain (≤10) or The product of the gain multiplied by Q (≤100). The operating amplifier should have the opening voltage gain at the highest frequency. At this frequency, it should be at least 50 times larger than the filter. In addition, the selected amplifier should have the rate of meeting the following requirements: the rotation rate ≥0.5 x (ωh vopp) x 10 6V/microsecond is the highest frequency of interest, VOPP is the output peak voltage.

This is a LMV721 used for microphone front placed. Since LMV721 is a low -noise and low -power computing amplifier, it makes it an ideal choice for the microphone front amplifier as a battery. LMV721 is connected with a reversal configuration. The resistor, R1 R2 4.7kΩ, set the reference halfway between VCC 3V and ground. Therefore, this is used for the use of op amp for single power supply. The gain of the front amplifier is 50 (34DB), which is set by the resistor R3 10kΩ and R4 500KΩ. The gain bandwidth accumulation is 10 MMV721. This is enough for most audio applications, because the audio range is usually between 20 Hertz and 20 kilo. A resistor R5 5KΩ is used for bias to resident microphone. C1 C2 4.7μF, placed in the input and output of OP to prevent DC voltage offset.